1. Field of the Invention
The present invention relates to a travel controlling apparatus of an unmanned vehicle which automatically travels on a preset traveling path in a mine, a stone quarry and the like.
2. Description of the Prior Art
Conventionally, as a traveling system of an unmanned vehicle automatically traveling on a preset traveling path, there has been well known a structure which employs both of a global positioning system navigation (hereinafter, refer to a GPS navigation) controlling an absolute position of the unmanned vehicle on the basis of a GPS receiver and an autonomous navigation detecting a traveling direction and a traveling distance of the unmanned vehicle so as to estimate and calculate a relative position and an azimuth on the basis of the absolute position by an inner angle sensor, thereby improving an accuracy of position measurement in accordance with a mutual complement between the both and traveling.
As the autonomous navigation, there have been known a dead reckoning navigation (a navigation of calculating a traveling distance by using a speed sensor and a moving distance sensor and estimating an azimuth by using a gyroscope and an earth magnetism sensor, thereby estimating the position and the azimuth of the vehicle), an inertial navigation (a navigation of estimating the position and the azimuth of the vehicle by using the gyroscope and an acceleration), and the like. Hereinafter, these navigation methods are totally called as an autonomy navigation.
FIG. 12 is a view describing a traveling system of an unmanned vehicle. In FIG. 12, a fixed base station 1 governs a control of an unmanned vehicle 10, and is structured such as to transmit a traveling path data and a vehicle control govern command to the unmanned vehicle 10 via a control communication antenna 2b and receive a vehicle state signs
Further, the unmanned vehicle 10 has a position measuring portion and a travel controlling portion The position measuring portion calculates an absolute coordinate value of a present position of the vehicle itself on the basis of positional information received from a plurality of satellites 3a to 3e by the GPS receiver via the GPS antenna 12a (the GPS navigation). At this time, the position measuring portion calculates a relative position and an azimuth from the absolute coordinate position given by the GPS on the basis of the traveling direction and the traveling distance, and subsequently estimates and calculates the present position and the azimuth (the autonomy navigation). Further, after traveling for a predetermined GPS positioning sampling time, the present position and the azimuth given by the relative position and the azimuth are corrected on the basis of the absolute position newly measured by the GPS. Further, the travel controlling portion calculates a traveling direction on the basis of a result of comparison between the position and the azimuth (the traveling direction) of the preset traveling path, and the present position and azimuth, and controls a steering and a vehicle speed so as to travel at a predetermined speed in the traveling direction. The structure is made such as to guide and travel the unmanned vehicle by repeating the processes mentioned above.
The GPS navigation mentioned above has a disadvantage that a calculating time from a timing starting the positioning and a timing time interval outputting a communication time lag and the positioning data from the GPS receiver to a final position measuring portion are slower than the position calculating time in accordance with the autonomy navigation. Further, there has been known a problem that an accuracy of positioning is deteriorated and there is a case that the positioning can not be executed due to a receiving environment of the satellites 3a to 3e, that is, a receiving environment reason such as a midair viewing property whether or not a midair of the unmanned vehicle is in a state of capable of normally receiving the GPS due to a peripheral quay wall, a forest, a structure or the like, an arrangement of satellites, a multipass at a time of receiving a radio wave reflected from a peripheral reflection subject, and the like, and in the case of DGPS (so-called differential type GPS), for the reason that a compensated information communication from the fixed base station 1 delays due to various reasons such as a mountain, the quay wall, the forest, the structure, the radio wave environment and the like.
On the contrary, the autonomy navigation is employed for compensating the disadvantage, and since the relative position is calculated by calculating a traveling distance for a short time at every predetermined time, for example, on the basis of measured values of the speed sensor and the azimuth sensor, it is possible to position at real time. However, since sensor errors of the speed sensor, the azimuth sensor and the like are accumulated, whereby there is a problem that the accuracy of positioning is deteriorated, it is intended to maintain an accuracy of position by compensating at every predetermined time on the basis of the GPS navigation mentioned above.
However, in the traveling system of the unmanned vehicle in accordance with the conventional art, there is the following problems.
(1) In the GPS navigation, there is a case that the accuracy of positioning is deteriorated due to an aggravation of the satellite receiving environment or an aggravation of the environment for receiving the compensated data from the base station in the case of DGPS, or the positioning can not be executed. In this case, an accuracy of a present position and a present azimuth which are calculated on the basis of the absolute position in accordance with the GPS navigation and the relative position and azimuth in accordance with the autonomous navigation is deteriorated, or when traveling only in accordance with the autonomous navigation, the accuracy of the present position and the present azimuth is deteriorated due to an accumulation of the measured errors. Accordingly, since an agency of guiding the unwanted vehicle is reduced, the vehicle control is damaged.
(2) In the case that the speed sensor, the azimuth sensor and the like in connection to the autonomous navigation are out of order, when traveling only in accordance with the GPS navigation, the positioning data output time interval in accordance with the GPS navigation is slow as mentioned above, the interval between the measured absolute coordinate position is too long, and an accuracy of travel guiding is reduced. Further, the accuracy of travel guiding is reduced due to the matter that the accuracy of speed and the accuracy of azimuth are deteriorated at a time of a low speed in the case of only the GPS navigation, the matter that the accuracy of positioning position and azimuth) is deteriorated for the reason that the GPS antenna track (corresponding to the azimuth in accordance with the GPS) is different from a direction of attitude of the vehicle at a time of turning, and the like.
Further, when the accuracy of positioning (position and azimuth) is reduced due to the deterioration of the receiving environment and the communication environment of the GPS navigation at this time, the accuracy of travel guiding is further reduced. Accordingly, in the case of the trouble in which the autonomous navigation can not be executed, the vehicle control is damaged, and a working ratio of the unmanned vehicle is reduced.
However, there is strongly desired a traveling system having a high reliability in which it is possible to securely guide and travel even in the case mentioned above.
The present invention is made by paying attention to the problems mentioned above, and an object of the present invention is to provide a travel controlling apparatus of an unmanned vehicle which can maintain a high accuracy of travel guiding even in the case that an accuracy of positioning of a GPS navigation or an autonomous navigation is deteriorated and a state that a positioning can not be executed is invited.
In order to achieve the object mentioned above, in accordance with a first aspect of the present invention, there is provided a travel controlling apparatus of an unmanned vehicle comprising:
a GPS receiver receiving a GPS signal so as to position an absolute coordinate position of a vehicle;
an autonomous navigation computing device measuring a traveling direction and a traveling distance of the vehicle so as to position a relative coordinate position and azimuth from a specific position of the vehicle on the basis of the measured result;
a position measuring portion calculating a present position and azimuth of the vehicle on the basis of the respective measured results of the GPS receiver and the autonomous navigation computing device; and
a travel controlling portion relatively comparing a position and an azimuth of a previously set traveling path with the present position and azimuth calculated by the position measuring portion so as to control the vehicle travel in such a manner as to make respective deviation values small,
wherein the travel controlling apparatus is provided with a roadside zone distance measuring device for measuring a distance from the vehicle to a roadside zone provided in a side of the traveling path, and the position measuring portion compensates at least one of a position positioned by the GPS receiver and/or a position and an azimuth positioned by the autonomous navigation computing device on the basis of the roadside zone distance measured by the roadside zone distance measuring device so as to determine the present position and azimuth.
In accordance with the first aspect of the present invention, since the present position and azimuth are calculated by compensating at least any one of the position measured by the GPS navigation and/or the position and the azimuth positioned by the autonomous navigation, on the basis of the measured value of the distance to the roadside zone (constituted by a shoulder of a road, an advertising display, a reflecting plate and the like), it is possible to reduce an error of the GPS positioning and a reduction of an accuracy of measurement of the position and the azimuth in accordance with the positioning error of the autonomous navigation, and it is possible to position the position and the azimuth of the vehicle with a higher accuracy. Further, even in the case that the positioning can not be executed in accordance with the GPS navigation or the autonomous navigation, or an abnormality of the positioning data is recognized, it is possible to determine the present position and azimuth having a reliability on the basis of the positioning data (the position and the azimuth) obtained by a normal one among the GPS navigation and the autonomous navigation, and the measured value of the roadside zone distance, so that it is possible to continue the guiding travel and it is possible to increase the working ratio of the unmanned vehicle. As a result, it is possible to structure the traveling system of the unmanned vehicle having a high reliability.
In accordance with a second aspect of the present invention, the structure is made such that on the basis of the first aspect, the position measuring portion judges a stability of the roadside zone from the measured value of the roadside zone distance, and compensates on the basis of the roadside zone distance at a time when the stability is normal
In accordance with the second aspect, it is judged that some abnormality is generated in an area in which the roadside zone is unstable, that is, the roadside zone discontinuously abuts against an area which is not previously set or the roadside zone largely changes in comparison with a preset rate of change, and the roadside zone distance measured in the area having the abnormality mentioned above is deemed to be an abnormal data. In this case, as a terrain intelligence of the roadside zone, there are previously set a rate of change of the roadside zone distance with respect to the shoulder placing range and the traveling road, the placing coordinates and the shape of the advertising display and the reflecting plate, and the like. Accordingly, the structure is made such as to execute the compensation on the basis of the roadside zone distance when the roadside zone is stable. Therefore, in the case that the roadside zone is unstable, it is possible to prevent the positioning (position and azimuth) accuracy from being reduced, by the compensation, it is possible to continue the automatic traveling and it is possible to increase the working ratio of the unmanned vehicle.
In accordance with a third aspect of the present invention, the structure is made such that on the basis of the first or second aspect, the compensation of the position measuring portion on the basis of the roadside zone distance is executed by a sensor fusion in correspondence to a positioning accuracy estimating value of the GPS receiver and/or a positioning accuracy estimating value of the autonomous computing device, and a positioning accuracy estimating value of the roadside zone distance measuring device.
In accordance with the third aspect, since the compensation position and the compensation azimuth are calculated by the sensor fusion in correspondence to the respective positioning accuracy estimating values of the GPS receiver, the autonomous navigation computing device and the roadside zone distance measuring device, it is possible to determine the position having the higher reliability. In this case, the positioning accuracy estimating values are estimated on the basis of the respective positioning results of the GPS receiver, the autonomous navigation computing device and the roadside zone distance measuring device, the information of the respective re d sensors, and an experimental judgement, may be estimated in real time or may be previously set to a predetermined value/